2cos (problem 3.3.5)

Percentage Accurate: 37.6% → 99.2%
Time: 21.7s
Alternatives: 15
Speedup: 1.9×

Specification

?
\[\begin{array}{l} \\ \cos \left(x + \varepsilon\right) - \cos x \end{array} \]
(FPCore (x eps) :precision binary64 (- (cos (+ x eps)) (cos x)))
double code(double x, double eps) {
	return cos((x + eps)) - cos(x);
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = cos((x + eps)) - cos(x)
end function
public static double code(double x, double eps) {
	return Math.cos((x + eps)) - Math.cos(x);
}
def code(x, eps):
	return math.cos((x + eps)) - math.cos(x)
function code(x, eps)
	return Float64(cos(Float64(x + eps)) - cos(x))
end
function tmp = code(x, eps)
	tmp = cos((x + eps)) - cos(x);
end
code[x_, eps_] := N[(N[Cos[N[(x + eps), $MachinePrecision]], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\cos \left(x + \varepsilon\right) - \cos x
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 15 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 37.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \cos \left(x + \varepsilon\right) - \cos x \end{array} \]
(FPCore (x eps) :precision binary64 (- (cos (+ x eps)) (cos x)))
double code(double x, double eps) {
	return cos((x + eps)) - cos(x);
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = cos((x + eps)) - cos(x)
end function
public static double code(double x, double eps) {
	return Math.cos((x + eps)) - Math.cos(x);
}
def code(x, eps):
	return math.cos((x + eps)) - math.cos(x)
function code(x, eps)
	return Float64(cos(Float64(x + eps)) - cos(x))
end
function tmp = code(x, eps)
	tmp = cos((x + eps)) - cos(x);
end
code[x_, eps_] := N[(N[Cos[N[(x + eps), $MachinePrecision]], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\cos \left(x + \varepsilon\right) - \cos x
\end{array}

Alternative 1: 99.2% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0033 \lor \neg \left(\varepsilon \leq 0.0037\right):\\ \;\;\;\;\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos \varepsilon \cdot \cos x\right) - \cos x\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \mathsf{fma}\left(-0.125, \varepsilon \cdot \left(\varepsilon \cdot \sin x\right), \sin x + \cos x \cdot \left(-0.020833333333333332 \cdot {\varepsilon}^{3} + \varepsilon \cdot 0.5\right)\right)\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -0.0033) (not (<= eps 0.0037)))
   (- (fma (sin eps) (- (sin x)) (* (cos eps) (cos x))) (cos x))
   (*
    -2.0
    (*
     (sin (* 0.5 (+ eps (- x x))))
     (fma
      -0.125
      (* eps (* eps (sin x)))
      (+
       (sin x)
       (*
        (cos x)
        (+ (* -0.020833333333333332 (pow eps 3.0)) (* eps 0.5)))))))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.0033) || !(eps <= 0.0037)) {
		tmp = fma(sin(eps), -sin(x), (cos(eps) * cos(x))) - cos(x);
	} else {
		tmp = -2.0 * (sin((0.5 * (eps + (x - x)))) * fma(-0.125, (eps * (eps * sin(x))), (sin(x) + (cos(x) * ((-0.020833333333333332 * pow(eps, 3.0)) + (eps * 0.5))))));
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if ((eps <= -0.0033) || !(eps <= 0.0037))
		tmp = Float64(fma(sin(eps), Float64(-sin(x)), Float64(cos(eps) * cos(x))) - cos(x));
	else
		tmp = Float64(-2.0 * Float64(sin(Float64(0.5 * Float64(eps + Float64(x - x)))) * fma(-0.125, Float64(eps * Float64(eps * sin(x))), Float64(sin(x) + Float64(cos(x) * Float64(Float64(-0.020833333333333332 * (eps ^ 3.0)) + Float64(eps * 0.5)))))));
	end
	return tmp
end
code[x_, eps_] := If[Or[LessEqual[eps, -0.0033], N[Not[LessEqual[eps, 0.0037]], $MachinePrecision]], N[(N[(N[Sin[eps], $MachinePrecision] * (-N[Sin[x], $MachinePrecision]) + N[(N[Cos[eps], $MachinePrecision] * N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], N[(-2.0 * N[(N[Sin[N[(0.5 * N[(eps + N[(x - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * N[(-0.125 * N[(eps * N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[Sin[x], $MachinePrecision] + N[(N[Cos[x], $MachinePrecision] * N[(N[(-0.020833333333333332 * N[Power[eps, 3.0], $MachinePrecision]), $MachinePrecision] + N[(eps * 0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.0033 \lor \neg \left(\varepsilon \leq 0.0037\right):\\
\;\;\;\;\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos \varepsilon \cdot \cos x\right) - \cos x\\

\mathbf{else}:\\
\;\;\;\;-2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \mathsf{fma}\left(-0.125, \varepsilon \cdot \left(\varepsilon \cdot \sin x\right), \sin x + \cos x \cdot \left(-0.020833333333333332 \cdot {\varepsilon}^{3} + \varepsilon \cdot 0.5\right)\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -0.0033 or 0.0037000000000000002 < eps

    1. Initial program 48.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. cos-sum99.1%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
      2. sub-neg99.1%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x \cdot \sin \varepsilon\right)\right)} - \cos x \]
    3. Applied egg-rr99.1%

      \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x \cdot \sin \varepsilon\right)\right)} - \cos x \]
    4. Step-by-step derivation
      1. +-commutative99.1%

        \[\leadsto \color{blue}{\left(\left(-\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \cos \varepsilon\right)} - \cos x \]
      2. distribute-lft-neg-in99.1%

        \[\leadsto \left(\color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon} + \cos x \cdot \cos \varepsilon\right) - \cos x \]
      3. *-commutative99.1%

        \[\leadsto \left(\color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)} + \cos x \cdot \cos \varepsilon\right) - \cos x \]
      4. fma-def99.1%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos x \cdot \cos \varepsilon\right)} - \cos x \]
      5. *-commutative99.1%

        \[\leadsto \mathsf{fma}\left(\sin \varepsilon, -\sin x, \color{blue}{\cos \varepsilon \cdot \cos x}\right) - \cos x \]
    5. Simplified99.1%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos \varepsilon \cdot \cos x\right)} - \cos x \]

    if -0.0033 < eps < 0.0037000000000000002

    1. Initial program 27.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos45.7%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv45.7%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. metadata-eval45.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. div-inv45.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      5. +-commutative45.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      6. metadata-eval45.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr45.7%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. *-commutative45.7%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \left(\left(x + \varepsilon\right) - x\right)\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      2. +-commutative45.7%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      3. associate--l+98.5%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      4. *-commutative98.5%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
      5. associate-+r+98.5%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right)\right) \]
      6. +-commutative98.5%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x + x\right)\right)}\right)\right) \]
    5. Simplified98.5%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)\right)} \]
    6. Taylor expanded in eps around 0 99.8%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \color{blue}{\left(-0.125 \cdot \left({\varepsilon}^{2} \cdot \sin x\right) + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + \left(0.5 \cdot \left(\varepsilon \cdot \cos x\right) + \sin x\right)\right)\right)}\right) \]
    7. Step-by-step derivation
      1. fma-def99.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \color{blue}{\mathsf{fma}\left(-0.125, {\varepsilon}^{2} \cdot \sin x, -0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + \left(0.5 \cdot \left(\varepsilon \cdot \cos x\right) + \sin x\right)\right)}\right) \]
      2. unpow299.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \mathsf{fma}\left(-0.125, \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \cdot \sin x, -0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + \left(0.5 \cdot \left(\varepsilon \cdot \cos x\right) + \sin x\right)\right)\right) \]
      3. associate-*l*99.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \mathsf{fma}\left(-0.125, \color{blue}{\varepsilon \cdot \left(\varepsilon \cdot \sin x\right)}, -0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + \left(0.5 \cdot \left(\varepsilon \cdot \cos x\right) + \sin x\right)\right)\right) \]
      4. *-commutative99.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \mathsf{fma}\left(-0.125, \varepsilon \cdot \color{blue}{\left(\sin x \cdot \varepsilon\right)}, -0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + \left(0.5 \cdot \left(\varepsilon \cdot \cos x\right) + \sin x\right)\right)\right) \]
      5. associate-+r+99.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \mathsf{fma}\left(-0.125, \varepsilon \cdot \left(\sin x \cdot \varepsilon\right), \color{blue}{\left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right) + \sin x}\right)\right) \]
      6. +-commutative99.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \mathsf{fma}\left(-0.125, \varepsilon \cdot \left(\sin x \cdot \varepsilon\right), \color{blue}{\sin x + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)}\right)\right) \]
      7. associate-*r*99.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \mathsf{fma}\left(-0.125, \varepsilon \cdot \left(\sin x \cdot \varepsilon\right), \sin x + \left(\color{blue}{\left(-0.020833333333333332 \cdot {\varepsilon}^{3}\right) \cdot \cos x} + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right)\right) \]
      8. associate-*r*99.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \mathsf{fma}\left(-0.125, \varepsilon \cdot \left(\sin x \cdot \varepsilon\right), \sin x + \left(\left(-0.020833333333333332 \cdot {\varepsilon}^{3}\right) \cdot \cos x + \color{blue}{\left(0.5 \cdot \varepsilon\right) \cdot \cos x}\right)\right)\right) \]
      9. +-rgt-identity99.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \mathsf{fma}\left(-0.125, \varepsilon \cdot \left(\sin x \cdot \varepsilon\right), \sin x + \left(\left(-0.020833333333333332 \cdot {\varepsilon}^{3}\right) \cdot \cos x + \color{blue}{\left(0.5 \cdot \varepsilon + 0\right)} \cdot \cos x\right)\right)\right) \]
      10. distribute-rgt-out99.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \mathsf{fma}\left(-0.125, \varepsilon \cdot \left(\sin x \cdot \varepsilon\right), \sin x + \color{blue}{\cos x \cdot \left(-0.020833333333333332 \cdot {\varepsilon}^{3} + \left(0.5 \cdot \varepsilon + 0\right)\right)}\right)\right) \]
      11. +-rgt-identity99.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \mathsf{fma}\left(-0.125, \varepsilon \cdot \left(\sin x \cdot \varepsilon\right), \sin x + \cos x \cdot \left(-0.020833333333333332 \cdot {\varepsilon}^{3} + \color{blue}{0.5 \cdot \varepsilon}\right)\right)\right) \]
    8. Simplified99.8%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \color{blue}{\mathsf{fma}\left(-0.125, \varepsilon \cdot \left(\sin x \cdot \varepsilon\right), \sin x + \cos x \cdot \left(-0.020833333333333332 \cdot {\varepsilon}^{3} + 0.5 \cdot \varepsilon\right)\right)}\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0033 \lor \neg \left(\varepsilon \leq 0.0037\right):\\ \;\;\;\;\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos \varepsilon \cdot \cos x\right) - \cos x\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \mathsf{fma}\left(-0.125, \varepsilon \cdot \left(\varepsilon \cdot \sin x\right), \sin x + \cos x \cdot \left(-0.020833333333333332 \cdot {\varepsilon}^{3} + \varepsilon \cdot 0.5\right)\right)\right)\\ \end{array} \]

Alternative 2: 99.2% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0026 \lor \neg \left(\varepsilon \leq 0.0034\right):\\ \;\;\;\;\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos \varepsilon \cdot \cos x\right) - \cos x\\ \mathbf{else}:\\ \;\;\;\;\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \varepsilon \cdot \sin x\right) + \cos x \cdot \left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -0.0026) (not (<= eps 0.0034)))
   (- (fma (sin eps) (- (sin x)) (* (cos eps) (cos x))) (cos x))
   (+
    (-
     (* -2.0 (* (pow eps 3.0) (* (sin x) -0.08333333333333333)))
     (* eps (sin x)))
    (*
     (cos x)
     (+ (* (* eps eps) -0.5) (* (pow eps 4.0) 0.041666666666666664))))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.0026) || !(eps <= 0.0034)) {
		tmp = fma(sin(eps), -sin(x), (cos(eps) * cos(x))) - cos(x);
	} else {
		tmp = ((-2.0 * (pow(eps, 3.0) * (sin(x) * -0.08333333333333333))) - (eps * sin(x))) + (cos(x) * (((eps * eps) * -0.5) + (pow(eps, 4.0) * 0.041666666666666664)));
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if ((eps <= -0.0026) || !(eps <= 0.0034))
		tmp = Float64(fma(sin(eps), Float64(-sin(x)), Float64(cos(eps) * cos(x))) - cos(x));
	else
		tmp = Float64(Float64(Float64(-2.0 * Float64((eps ^ 3.0) * Float64(sin(x) * -0.08333333333333333))) - Float64(eps * sin(x))) + Float64(cos(x) * Float64(Float64(Float64(eps * eps) * -0.5) + Float64((eps ^ 4.0) * 0.041666666666666664))));
	end
	return tmp
end
code[x_, eps_] := If[Or[LessEqual[eps, -0.0026], N[Not[LessEqual[eps, 0.0034]], $MachinePrecision]], N[(N[(N[Sin[eps], $MachinePrecision] * (-N[Sin[x], $MachinePrecision]) + N[(N[Cos[eps], $MachinePrecision] * N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], N[(N[(N[(-2.0 * N[(N[Power[eps, 3.0], $MachinePrecision] * N[(N[Sin[x], $MachinePrecision] * -0.08333333333333333), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[Cos[x], $MachinePrecision] * N[(N[(N[(eps * eps), $MachinePrecision] * -0.5), $MachinePrecision] + N[(N[Power[eps, 4.0], $MachinePrecision] * 0.041666666666666664), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.0026 \lor \neg \left(\varepsilon \leq 0.0034\right):\\
\;\;\;\;\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos \varepsilon \cdot \cos x\right) - \cos x\\

\mathbf{else}:\\
\;\;\;\;\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \varepsilon \cdot \sin x\right) + \cos x \cdot \left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -0.0025999999999999999 or 0.00339999999999999981 < eps

    1. Initial program 48.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. cos-sum99.1%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
      2. sub-neg99.1%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x \cdot \sin \varepsilon\right)\right)} - \cos x \]
    3. Applied egg-rr99.1%

      \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x \cdot \sin \varepsilon\right)\right)} - \cos x \]
    4. Step-by-step derivation
      1. +-commutative99.1%

        \[\leadsto \color{blue}{\left(\left(-\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \cos \varepsilon\right)} - \cos x \]
      2. distribute-lft-neg-in99.1%

        \[\leadsto \left(\color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon} + \cos x \cdot \cos \varepsilon\right) - \cos x \]
      3. *-commutative99.1%

        \[\leadsto \left(\color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)} + \cos x \cdot \cos \varepsilon\right) - \cos x \]
      4. fma-def99.1%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos x \cdot \cos \varepsilon\right)} - \cos x \]
      5. *-commutative99.1%

        \[\leadsto \mathsf{fma}\left(\sin \varepsilon, -\sin x, \color{blue}{\cos \varepsilon \cdot \cos x}\right) - \cos x \]
    5. Simplified99.1%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos \varepsilon \cdot \cos x\right)} - \cos x \]

    if -0.0025999999999999999 < eps < 0.00339999999999999981

    1. Initial program 27.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. add-log-exp27.3%

        \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
    3. Applied egg-rr27.3%

      \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
    4. Step-by-step derivation
      1. add-log-exp27.3%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) - \cos x} \]
      2. diff-cos45.7%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      3. +-commutative45.7%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. associate-+r-98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      5. +-inverses98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + \color{blue}{0}}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      6. +-commutative98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right)\right) \]
      7. associate-+r+98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right)\right) \]
    5. Applied egg-rr98.5%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right)} \]
    6. Step-by-step derivation
      1. +-rgt-identity98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon}}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right) \]
    7. Simplified98.5%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right)} \]
    8. Taylor expanded in eps around 0 99.8%

      \[\leadsto \color{blue}{0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + \left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \left(-1 \cdot \left(\varepsilon \cdot \sin x\right) + -2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right)\right)\right)} \]
    9. Step-by-step derivation
      1. associate-+r+99.8%

        \[\leadsto \color{blue}{\left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) + \left(-1 \cdot \left(\varepsilon \cdot \sin x\right) + -2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right)\right)} \]
      2. +-commutative99.8%

        \[\leadsto \color{blue}{\left(-1 \cdot \left(\varepsilon \cdot \sin x\right) + -2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right)\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right)} \]
      3. +-commutative99.8%

        \[\leadsto \color{blue}{\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)\right)} + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      4. mul-1-neg99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)}\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      5. unsub-neg99.8%

        \[\leadsto \color{blue}{\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right) - \varepsilon \cdot \sin x\right)} + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      6. distribute-rgt-out99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \color{blue}{\left(\sin x \cdot \left(-0.0625 + -0.020833333333333332\right)\right)}\right) - \varepsilon \cdot \sin x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      7. metadata-eval99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot \color{blue}{-0.08333333333333333}\right)\right) - \varepsilon \cdot \sin x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      8. *-commutative99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \color{blue}{\sin x \cdot \varepsilon}\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
    10. Simplified99.8%

      \[\leadsto \color{blue}{\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \sin x \cdot \varepsilon\right) + \cos x \cdot \mathsf{fma}\left(\varepsilon \cdot \varepsilon, -0.5, {\varepsilon}^{4} \cdot 0.041666666666666664\right)} \]
    11. Step-by-step derivation
      1. fma-udef99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \sin x \cdot \varepsilon\right) + \cos x \cdot \color{blue}{\left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)} \]
    12. Applied egg-rr99.8%

      \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \sin x \cdot \varepsilon\right) + \cos x \cdot \color{blue}{\left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0026 \lor \neg \left(\varepsilon \leq 0.0034\right):\\ \;\;\;\;\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos \varepsilon \cdot \cos x\right) - \cos x\\ \mathbf{else}:\\ \;\;\;\;\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \varepsilon \cdot \sin x\right) + \cos x \cdot \left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)\\ \end{array} \]

Alternative 3: 99.2% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \varepsilon \cdot \cos x\\ \mathbf{if}\;\varepsilon \leq -0.0025:\\ \;\;\;\;\left(t_0 - \sin \varepsilon \cdot \sin x\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 0.0034:\\ \;\;\;\;\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \varepsilon \cdot \sin x\right) + \cos x \cdot \left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)\\ \mathbf{else}:\\ \;\;\;\;t_0 - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (* (cos eps) (cos x))))
   (if (<= eps -0.0025)
     (- (- t_0 (* (sin eps) (sin x))) (cos x))
     (if (<= eps 0.0034)
       (+
        (-
         (* -2.0 (* (pow eps 3.0) (* (sin x) -0.08333333333333333)))
         (* eps (sin x)))
        (*
         (cos x)
         (+ (* (* eps eps) -0.5) (* (pow eps 4.0) 0.041666666666666664))))
       (- t_0 (fma (sin eps) (sin x) (cos x)))))))
double code(double x, double eps) {
	double t_0 = cos(eps) * cos(x);
	double tmp;
	if (eps <= -0.0025) {
		tmp = (t_0 - (sin(eps) * sin(x))) - cos(x);
	} else if (eps <= 0.0034) {
		tmp = ((-2.0 * (pow(eps, 3.0) * (sin(x) * -0.08333333333333333))) - (eps * sin(x))) + (cos(x) * (((eps * eps) * -0.5) + (pow(eps, 4.0) * 0.041666666666666664)));
	} else {
		tmp = t_0 - fma(sin(eps), sin(x), cos(x));
	}
	return tmp;
}
function code(x, eps)
	t_0 = Float64(cos(eps) * cos(x))
	tmp = 0.0
	if (eps <= -0.0025)
		tmp = Float64(Float64(t_0 - Float64(sin(eps) * sin(x))) - cos(x));
	elseif (eps <= 0.0034)
		tmp = Float64(Float64(Float64(-2.0 * Float64((eps ^ 3.0) * Float64(sin(x) * -0.08333333333333333))) - Float64(eps * sin(x))) + Float64(cos(x) * Float64(Float64(Float64(eps * eps) * -0.5) + Float64((eps ^ 4.0) * 0.041666666666666664))));
	else
		tmp = Float64(t_0 - fma(sin(eps), sin(x), cos(x)));
	end
	return tmp
end
code[x_, eps_] := Block[{t$95$0 = N[(N[Cos[eps], $MachinePrecision] * N[Cos[x], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[eps, -0.0025], N[(N[(t$95$0 - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 0.0034], N[(N[(N[(-2.0 * N[(N[Power[eps, 3.0], $MachinePrecision] * N[(N[Sin[x], $MachinePrecision] * -0.08333333333333333), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[Cos[x], $MachinePrecision] * N[(N[(N[(eps * eps), $MachinePrecision] * -0.5), $MachinePrecision] + N[(N[Power[eps, 4.0], $MachinePrecision] * 0.041666666666666664), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(t$95$0 - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision] + N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos \varepsilon \cdot \cos x\\
\mathbf{if}\;\varepsilon \leq -0.0025:\\
\;\;\;\;\left(t_0 - \sin \varepsilon \cdot \sin x\right) - \cos x\\

\mathbf{elif}\;\varepsilon \leq 0.0034:\\
\;\;\;\;\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \varepsilon \cdot \sin x\right) + \cos x \cdot \left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)\\

\mathbf{else}:\\
\;\;\;\;t_0 - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -0.00250000000000000005

    1. Initial program 45.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. cos-sum99.1%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
    3. Applied egg-rr99.1%

      \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]

    if -0.00250000000000000005 < eps < 0.00339999999999999981

    1. Initial program 27.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. add-log-exp27.3%

        \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
    3. Applied egg-rr27.3%

      \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
    4. Step-by-step derivation
      1. add-log-exp27.3%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) - \cos x} \]
      2. diff-cos45.7%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      3. +-commutative45.7%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. associate-+r-98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      5. +-inverses98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + \color{blue}{0}}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      6. +-commutative98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right)\right) \]
      7. associate-+r+98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right)\right) \]
    5. Applied egg-rr98.5%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right)} \]
    6. Step-by-step derivation
      1. +-rgt-identity98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon}}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right) \]
    7. Simplified98.5%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right)} \]
    8. Taylor expanded in eps around 0 99.8%

      \[\leadsto \color{blue}{0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + \left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \left(-1 \cdot \left(\varepsilon \cdot \sin x\right) + -2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right)\right)\right)} \]
    9. Step-by-step derivation
      1. associate-+r+99.8%

        \[\leadsto \color{blue}{\left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) + \left(-1 \cdot \left(\varepsilon \cdot \sin x\right) + -2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right)\right)} \]
      2. +-commutative99.8%

        \[\leadsto \color{blue}{\left(-1 \cdot \left(\varepsilon \cdot \sin x\right) + -2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right)\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right)} \]
      3. +-commutative99.8%

        \[\leadsto \color{blue}{\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)\right)} + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      4. mul-1-neg99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)}\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      5. unsub-neg99.8%

        \[\leadsto \color{blue}{\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right) - \varepsilon \cdot \sin x\right)} + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      6. distribute-rgt-out99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \color{blue}{\left(\sin x \cdot \left(-0.0625 + -0.020833333333333332\right)\right)}\right) - \varepsilon \cdot \sin x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      7. metadata-eval99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot \color{blue}{-0.08333333333333333}\right)\right) - \varepsilon \cdot \sin x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      8. *-commutative99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \color{blue}{\sin x \cdot \varepsilon}\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
    10. Simplified99.8%

      \[\leadsto \color{blue}{\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \sin x \cdot \varepsilon\right) + \cos x \cdot \mathsf{fma}\left(\varepsilon \cdot \varepsilon, -0.5, {\varepsilon}^{4} \cdot 0.041666666666666664\right)} \]
    11. Step-by-step derivation
      1. fma-udef99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \sin x \cdot \varepsilon\right) + \cos x \cdot \color{blue}{\left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)} \]
    12. Applied egg-rr99.8%

      \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \sin x \cdot \varepsilon\right) + \cos x \cdot \color{blue}{\left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)} \]

    if 0.00339999999999999981 < eps

    1. Initial program 51.9%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg51.9%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum99.0%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
      3. associate-+l-98.9%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      4. fma-neg98.9%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    3. Applied egg-rr98.9%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    4. Step-by-step derivation
      1. fma-neg98.9%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      2. *-commutative98.9%

        \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x} - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right) \]
      3. *-commutative98.9%

        \[\leadsto \cos \varepsilon \cdot \cos x - \left(\color{blue}{\sin \varepsilon \cdot \sin x} - \left(-\cos x\right)\right) \]
      4. fma-neg99.1%

        \[\leadsto \cos \varepsilon \cdot \cos x - \color{blue}{\mathsf{fma}\left(\sin \varepsilon, \sin x, -\left(-\cos x\right)\right)} \]
      5. remove-double-neg99.1%

        \[\leadsto \cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \color{blue}{\cos x}\right) \]
    5. Simplified99.1%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0025:\\ \;\;\;\;\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 0.0034:\\ \;\;\;\;\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \varepsilon \cdot \sin x\right) + \cos x \cdot \left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)\\ \end{array} \]

Alternative 4: 99.2% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.00265 \lor \neg \left(\varepsilon \leq 0.0031\right):\\ \;\;\;\;\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right) - \cos x\\ \mathbf{else}:\\ \;\;\;\;\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \varepsilon \cdot \sin x\right) + \cos x \cdot \left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -0.00265) (not (<= eps 0.0031)))
   (- (- (* (cos eps) (cos x)) (* (sin eps) (sin x))) (cos x))
   (+
    (-
     (* -2.0 (* (pow eps 3.0) (* (sin x) -0.08333333333333333)))
     (* eps (sin x)))
    (*
     (cos x)
     (+ (* (* eps eps) -0.5) (* (pow eps 4.0) 0.041666666666666664))))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.00265) || !(eps <= 0.0031)) {
		tmp = ((cos(eps) * cos(x)) - (sin(eps) * sin(x))) - cos(x);
	} else {
		tmp = ((-2.0 * (pow(eps, 3.0) * (sin(x) * -0.08333333333333333))) - (eps * sin(x))) + (cos(x) * (((eps * eps) * -0.5) + (pow(eps, 4.0) * 0.041666666666666664)));
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-0.00265d0)) .or. (.not. (eps <= 0.0031d0))) then
        tmp = ((cos(eps) * cos(x)) - (sin(eps) * sin(x))) - cos(x)
    else
        tmp = (((-2.0d0) * ((eps ** 3.0d0) * (sin(x) * (-0.08333333333333333d0)))) - (eps * sin(x))) + (cos(x) * (((eps * eps) * (-0.5d0)) + ((eps ** 4.0d0) * 0.041666666666666664d0)))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.00265) || !(eps <= 0.0031)) {
		tmp = ((Math.cos(eps) * Math.cos(x)) - (Math.sin(eps) * Math.sin(x))) - Math.cos(x);
	} else {
		tmp = ((-2.0 * (Math.pow(eps, 3.0) * (Math.sin(x) * -0.08333333333333333))) - (eps * Math.sin(x))) + (Math.cos(x) * (((eps * eps) * -0.5) + (Math.pow(eps, 4.0) * 0.041666666666666664)));
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -0.00265) or not (eps <= 0.0031):
		tmp = ((math.cos(eps) * math.cos(x)) - (math.sin(eps) * math.sin(x))) - math.cos(x)
	else:
		tmp = ((-2.0 * (math.pow(eps, 3.0) * (math.sin(x) * -0.08333333333333333))) - (eps * math.sin(x))) + (math.cos(x) * (((eps * eps) * -0.5) + (math.pow(eps, 4.0) * 0.041666666666666664)))
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -0.00265) || !(eps <= 0.0031))
		tmp = Float64(Float64(Float64(cos(eps) * cos(x)) - Float64(sin(eps) * sin(x))) - cos(x));
	else
		tmp = Float64(Float64(Float64(-2.0 * Float64((eps ^ 3.0) * Float64(sin(x) * -0.08333333333333333))) - Float64(eps * sin(x))) + Float64(cos(x) * Float64(Float64(Float64(eps * eps) * -0.5) + Float64((eps ^ 4.0) * 0.041666666666666664))));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -0.00265) || ~((eps <= 0.0031)))
		tmp = ((cos(eps) * cos(x)) - (sin(eps) * sin(x))) - cos(x);
	else
		tmp = ((-2.0 * ((eps ^ 3.0) * (sin(x) * -0.08333333333333333))) - (eps * sin(x))) + (cos(x) * (((eps * eps) * -0.5) + ((eps ^ 4.0) * 0.041666666666666664)));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -0.00265], N[Not[LessEqual[eps, 0.0031]], $MachinePrecision]], N[(N[(N[(N[Cos[eps], $MachinePrecision] * N[Cos[x], $MachinePrecision]), $MachinePrecision] - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], N[(N[(N[(-2.0 * N[(N[Power[eps, 3.0], $MachinePrecision] * N[(N[Sin[x], $MachinePrecision] * -0.08333333333333333), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[Cos[x], $MachinePrecision] * N[(N[(N[(eps * eps), $MachinePrecision] * -0.5), $MachinePrecision] + N[(N[Power[eps, 4.0], $MachinePrecision] * 0.041666666666666664), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.00265 \lor \neg \left(\varepsilon \leq 0.0031\right):\\
\;\;\;\;\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right) - \cos x\\

\mathbf{else}:\\
\;\;\;\;\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \varepsilon \cdot \sin x\right) + \cos x \cdot \left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -0.00265000000000000001 or 0.00309999999999999989 < eps

    1. Initial program 48.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. cos-sum99.1%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
    3. Applied egg-rr99.1%

      \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]

    if -0.00265000000000000001 < eps < 0.00309999999999999989

    1. Initial program 27.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. add-log-exp27.3%

        \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
    3. Applied egg-rr27.3%

      \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
    4. Step-by-step derivation
      1. add-log-exp27.3%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) - \cos x} \]
      2. diff-cos45.7%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      3. +-commutative45.7%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. associate-+r-98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      5. +-inverses98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + \color{blue}{0}}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      6. +-commutative98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right)\right) \]
      7. associate-+r+98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right)\right) \]
    5. Applied egg-rr98.5%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right)} \]
    6. Step-by-step derivation
      1. +-rgt-identity98.5%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon}}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right) \]
    7. Simplified98.5%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right)} \]
    8. Taylor expanded in eps around 0 99.8%

      \[\leadsto \color{blue}{0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + \left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \left(-1 \cdot \left(\varepsilon \cdot \sin x\right) + -2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right)\right)\right)} \]
    9. Step-by-step derivation
      1. associate-+r+99.8%

        \[\leadsto \color{blue}{\left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) + \left(-1 \cdot \left(\varepsilon \cdot \sin x\right) + -2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right)\right)} \]
      2. +-commutative99.8%

        \[\leadsto \color{blue}{\left(-1 \cdot \left(\varepsilon \cdot \sin x\right) + -2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right)\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right)} \]
      3. +-commutative99.8%

        \[\leadsto \color{blue}{\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)\right)} + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      4. mul-1-neg99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)}\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      5. unsub-neg99.8%

        \[\leadsto \color{blue}{\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(-0.0625 \cdot \sin x + -0.020833333333333332 \cdot \sin x\right)\right) - \varepsilon \cdot \sin x\right)} + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      6. distribute-rgt-out99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \color{blue}{\left(\sin x \cdot \left(-0.0625 + -0.020833333333333332\right)\right)}\right) - \varepsilon \cdot \sin x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      7. metadata-eval99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot \color{blue}{-0.08333333333333333}\right)\right) - \varepsilon \cdot \sin x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
      8. *-commutative99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \color{blue}{\sin x \cdot \varepsilon}\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)\right) \]
    10. Simplified99.8%

      \[\leadsto \color{blue}{\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \sin x \cdot \varepsilon\right) + \cos x \cdot \mathsf{fma}\left(\varepsilon \cdot \varepsilon, -0.5, {\varepsilon}^{4} \cdot 0.041666666666666664\right)} \]
    11. Step-by-step derivation
      1. fma-udef99.8%

        \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \sin x \cdot \varepsilon\right) + \cos x \cdot \color{blue}{\left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)} \]
    12. Applied egg-rr99.8%

      \[\leadsto \left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \sin x \cdot \varepsilon\right) + \cos x \cdot \color{blue}{\left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.00265 \lor \neg \left(\varepsilon \leq 0.0031\right):\\ \;\;\;\;\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right) - \cos x\\ \mathbf{else}:\\ \;\;\;\;\left(-2 \cdot \left({\varepsilon}^{3} \cdot \left(\sin x \cdot -0.08333333333333333\right)\right) - \varepsilon \cdot \sin x\right) + \cos x \cdot \left(\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 + {\varepsilon}^{4} \cdot 0.041666666666666664\right)\\ \end{array} \]

Alternative 5: 99.1% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -2.7 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 4.3 \cdot 10^{-5}\right):\\ \;\;\;\;\cos \varepsilon \cdot \cos x - \left(\cos x + \sin \varepsilon \cdot \sin x\right)\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \varepsilon \cdot \sin x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -2.7e-5) (not (<= eps 4.3e-5)))
   (- (* (cos eps) (cos x)) (+ (cos x) (* (sin eps) (sin x))))
   (- (* -0.5 (* eps (* eps (cos x)))) (* eps (sin x)))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -2.7e-5) || !(eps <= 4.3e-5)) {
		tmp = (cos(eps) * cos(x)) - (cos(x) + (sin(eps) * sin(x)));
	} else {
		tmp = (-0.5 * (eps * (eps * cos(x)))) - (eps * sin(x));
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-2.7d-5)) .or. (.not. (eps <= 4.3d-5))) then
        tmp = (cos(eps) * cos(x)) - (cos(x) + (sin(eps) * sin(x)))
    else
        tmp = ((-0.5d0) * (eps * (eps * cos(x)))) - (eps * sin(x))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -2.7e-5) || !(eps <= 4.3e-5)) {
		tmp = (Math.cos(eps) * Math.cos(x)) - (Math.cos(x) + (Math.sin(eps) * Math.sin(x)));
	} else {
		tmp = (-0.5 * (eps * (eps * Math.cos(x)))) - (eps * Math.sin(x));
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -2.7e-5) or not (eps <= 4.3e-5):
		tmp = (math.cos(eps) * math.cos(x)) - (math.cos(x) + (math.sin(eps) * math.sin(x)))
	else:
		tmp = (-0.5 * (eps * (eps * math.cos(x)))) - (eps * math.sin(x))
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -2.7e-5) || !(eps <= 4.3e-5))
		tmp = Float64(Float64(cos(eps) * cos(x)) - Float64(cos(x) + Float64(sin(eps) * sin(x))));
	else
		tmp = Float64(Float64(-0.5 * Float64(eps * Float64(eps * cos(x)))) - Float64(eps * sin(x)));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -2.7e-5) || ~((eps <= 4.3e-5)))
		tmp = (cos(eps) * cos(x)) - (cos(x) + (sin(eps) * sin(x)));
	else
		tmp = (-0.5 * (eps * (eps * cos(x)))) - (eps * sin(x));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -2.7e-5], N[Not[LessEqual[eps, 4.3e-5]], $MachinePrecision]], N[(N[(N[Cos[eps], $MachinePrecision] * N[Cos[x], $MachinePrecision]), $MachinePrecision] - N[(N[Cos[x], $MachinePrecision] + N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(-0.5 * N[(eps * N[(eps * N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -2.7 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 4.3 \cdot 10^{-5}\right):\\
\;\;\;\;\cos \varepsilon \cdot \cos x - \left(\cos x + \sin \varepsilon \cdot \sin x\right)\\

\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \varepsilon \cdot \sin x\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -2.6999999999999999e-5 or 4.3000000000000002e-5 < eps

    1. Initial program 47.9%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg47.9%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum98.6%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
      3. associate-+l-98.5%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      4. fma-neg98.5%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    3. Applied egg-rr98.5%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    4. Taylor expanded in x around -inf 98.5%

      \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\cos x + \sin x \cdot \sin \varepsilon\right)} \]

    if -2.6999999999999999e-5 < eps < 4.3000000000000002e-5

    1. Initial program 27.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 99.8%

      \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. mul-1-neg99.8%

        \[\leadsto -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)} \]
      2. unsub-neg99.8%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) - \varepsilon \cdot \sin x} \]
      3. unpow299.8%

        \[\leadsto -0.5 \cdot \left(\color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \cdot \cos x\right) - \varepsilon \cdot \sin x \]
      4. associate-*l*99.8%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right)} - \varepsilon \cdot \sin x \]
    4. Simplified99.8%

      \[\leadsto \color{blue}{-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \varepsilon \cdot \sin x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -2.7 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 4.3 \cdot 10^{-5}\right):\\ \;\;\;\;\cos \varepsilon \cdot \cos x - \left(\cos x + \sin \varepsilon \cdot \sin x\right)\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \varepsilon \cdot \sin x\\ \end{array} \]

Alternative 6: 99.1% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -3.4 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 3.1 \cdot 10^{-5}\right):\\ \;\;\;\;\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right) - \cos x\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \varepsilon \cdot \sin x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -3.4e-5) (not (<= eps 3.1e-5)))
   (- (- (* (cos eps) (cos x)) (* (sin eps) (sin x))) (cos x))
   (- (* -0.5 (* eps (* eps (cos x)))) (* eps (sin x)))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -3.4e-5) || !(eps <= 3.1e-5)) {
		tmp = ((cos(eps) * cos(x)) - (sin(eps) * sin(x))) - cos(x);
	} else {
		tmp = (-0.5 * (eps * (eps * cos(x)))) - (eps * sin(x));
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-3.4d-5)) .or. (.not. (eps <= 3.1d-5))) then
        tmp = ((cos(eps) * cos(x)) - (sin(eps) * sin(x))) - cos(x)
    else
        tmp = ((-0.5d0) * (eps * (eps * cos(x)))) - (eps * sin(x))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -3.4e-5) || !(eps <= 3.1e-5)) {
		tmp = ((Math.cos(eps) * Math.cos(x)) - (Math.sin(eps) * Math.sin(x))) - Math.cos(x);
	} else {
		tmp = (-0.5 * (eps * (eps * Math.cos(x)))) - (eps * Math.sin(x));
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -3.4e-5) or not (eps <= 3.1e-5):
		tmp = ((math.cos(eps) * math.cos(x)) - (math.sin(eps) * math.sin(x))) - math.cos(x)
	else:
		tmp = (-0.5 * (eps * (eps * math.cos(x)))) - (eps * math.sin(x))
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -3.4e-5) || !(eps <= 3.1e-5))
		tmp = Float64(Float64(Float64(cos(eps) * cos(x)) - Float64(sin(eps) * sin(x))) - cos(x));
	else
		tmp = Float64(Float64(-0.5 * Float64(eps * Float64(eps * cos(x)))) - Float64(eps * sin(x)));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -3.4e-5) || ~((eps <= 3.1e-5)))
		tmp = ((cos(eps) * cos(x)) - (sin(eps) * sin(x))) - cos(x);
	else
		tmp = (-0.5 * (eps * (eps * cos(x)))) - (eps * sin(x));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -3.4e-5], N[Not[LessEqual[eps, 3.1e-5]], $MachinePrecision]], N[(N[(N[(N[Cos[eps], $MachinePrecision] * N[Cos[x], $MachinePrecision]), $MachinePrecision] - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], N[(N[(-0.5 * N[(eps * N[(eps * N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -3.4 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 3.1 \cdot 10^{-5}\right):\\
\;\;\;\;\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right) - \cos x\\

\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \varepsilon \cdot \sin x\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -3.4e-5 or 3.10000000000000014e-5 < eps

    1. Initial program 47.9%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. cos-sum98.6%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
    3. Applied egg-rr98.6%

      \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]

    if -3.4e-5 < eps < 3.10000000000000014e-5

    1. Initial program 27.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 99.8%

      \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. mul-1-neg99.8%

        \[\leadsto -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)} \]
      2. unsub-neg99.8%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) - \varepsilon \cdot \sin x} \]
      3. unpow299.8%

        \[\leadsto -0.5 \cdot \left(\color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \cdot \cos x\right) - \varepsilon \cdot \sin x \]
      4. associate-*l*99.8%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right)} - \varepsilon \cdot \sin x \]
    4. Simplified99.8%

      \[\leadsto \color{blue}{-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \varepsilon \cdot \sin x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -3.4 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 3.1 \cdot 10^{-5}\right):\\ \;\;\;\;\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right) - \cos x\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \varepsilon \cdot \sin x\\ \end{array} \]

Alternative 7: 67.5% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\cos \left(\varepsilon + x\right) - \cos x \leq -5 \cdot 10^{-7}:\\ \;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \left(\sin x \cdot \sin \left(\frac{\varepsilon}{2}\right)\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= (- (cos (+ eps x)) (cos x)) -5e-7)
   (* -2.0 (pow (sin (* eps 0.5)) 2.0))
   (* -2.0 (* (sin x) (sin (/ eps 2.0))))))
double code(double x, double eps) {
	double tmp;
	if ((cos((eps + x)) - cos(x)) <= -5e-7) {
		tmp = -2.0 * pow(sin((eps * 0.5)), 2.0);
	} else {
		tmp = -2.0 * (sin(x) * sin((eps / 2.0)));
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((cos((eps + x)) - cos(x)) <= (-5d-7)) then
        tmp = (-2.0d0) * (sin((eps * 0.5d0)) ** 2.0d0)
    else
        tmp = (-2.0d0) * (sin(x) * sin((eps / 2.0d0)))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((Math.cos((eps + x)) - Math.cos(x)) <= -5e-7) {
		tmp = -2.0 * Math.pow(Math.sin((eps * 0.5)), 2.0);
	} else {
		tmp = -2.0 * (Math.sin(x) * Math.sin((eps / 2.0)));
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (math.cos((eps + x)) - math.cos(x)) <= -5e-7:
		tmp = -2.0 * math.pow(math.sin((eps * 0.5)), 2.0)
	else:
		tmp = -2.0 * (math.sin(x) * math.sin((eps / 2.0)))
	return tmp
function code(x, eps)
	tmp = 0.0
	if (Float64(cos(Float64(eps + x)) - cos(x)) <= -5e-7)
		tmp = Float64(-2.0 * (sin(Float64(eps * 0.5)) ^ 2.0));
	else
		tmp = Float64(-2.0 * Float64(sin(x) * sin(Float64(eps / 2.0))));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((cos((eps + x)) - cos(x)) <= -5e-7)
		tmp = -2.0 * (sin((eps * 0.5)) ^ 2.0);
	else
		tmp = -2.0 * (sin(x) * sin((eps / 2.0)));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[N[(N[Cos[N[(eps + x), $MachinePrecision]], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], -5e-7], N[(-2.0 * N[Power[N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision], N[(-2.0 * N[(N[Sin[x], $MachinePrecision] * N[Sin[N[(eps / 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\cos \left(\varepsilon + x\right) - \cos x \leq -5 \cdot 10^{-7}:\\
\;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\

\mathbf{else}:\\
\;\;\;\;-2 \cdot \left(\sin x \cdot \sin \left(\frac{\varepsilon}{2}\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (cos.f64 (+.f64 x eps)) (cos.f64 x)) < -4.99999999999999977e-7

    1. Initial program 74.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos74.8%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv74.8%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. metadata-eval74.8%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. div-inv74.8%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      5. +-commutative74.8%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      6. metadata-eval74.8%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr74.8%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. *-commutative74.8%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \left(\left(x + \varepsilon\right) - x\right)\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      2. +-commutative74.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      3. associate--l+74.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      4. *-commutative74.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
      5. associate-+r+75.0%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right)\right) \]
      6. +-commutative75.0%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x + x\right)\right)}\right)\right) \]
    5. Simplified75.0%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)\right)} \]
    6. Taylor expanded in x around 0 74.8%

      \[\leadsto -2 \cdot \color{blue}{{\sin \left(0.5 \cdot \varepsilon\right)}^{2}} \]

    if -4.99999999999999977e-7 < (-.f64 (cos.f64 (+.f64 x eps)) (cos.f64 x))

    1. Initial program 20.5%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. add-log-exp20.5%

        \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
    3. Applied egg-rr20.5%

      \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
    4. Step-by-step derivation
      1. add-log-exp20.5%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) - \cos x} \]
      2. diff-cos33.4%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      3. +-commutative33.4%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. associate-+r-72.0%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      5. +-inverses72.0%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + \color{blue}{0}}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      6. +-commutative72.0%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right)\right) \]
      7. associate-+r+72.0%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right)\right) \]
    5. Applied egg-rr72.0%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right)} \]
    6. Step-by-step derivation
      1. +-rgt-identity72.0%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon}}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right) \]
    7. Simplified72.0%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right)} \]
    8. Taylor expanded in eps around 0 59.4%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \color{blue}{\sin x}\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification64.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\cos \left(\varepsilon + x\right) - \cos x \leq -5 \cdot 10^{-7}:\\ \;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \left(\sin x \cdot \sin \left(\frac{\varepsilon}{2}\right)\right)\\ \end{array} \]

Alternative 8: 76.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.026:\\ \;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\ \mathbf{elif}\;\varepsilon \leq 0.001:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\cos \varepsilon - \cos x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -0.026)
   (* -2.0 (pow (sin (* eps 0.5)) 2.0))
   (if (<= eps 0.001)
     (- (* -0.5 (* eps (* eps (cos x)))) (* eps (sin x)))
     (- (cos eps) (cos x)))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -0.026) {
		tmp = -2.0 * pow(sin((eps * 0.5)), 2.0);
	} else if (eps <= 0.001) {
		tmp = (-0.5 * (eps * (eps * cos(x)))) - (eps * sin(x));
	} else {
		tmp = cos(eps) - cos(x);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if (eps <= (-0.026d0)) then
        tmp = (-2.0d0) * (sin((eps * 0.5d0)) ** 2.0d0)
    else if (eps <= 0.001d0) then
        tmp = ((-0.5d0) * (eps * (eps * cos(x)))) - (eps * sin(x))
    else
        tmp = cos(eps) - cos(x)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if (eps <= -0.026) {
		tmp = -2.0 * Math.pow(Math.sin((eps * 0.5)), 2.0);
	} else if (eps <= 0.001) {
		tmp = (-0.5 * (eps * (eps * Math.cos(x)))) - (eps * Math.sin(x));
	} else {
		tmp = Math.cos(eps) - Math.cos(x);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if eps <= -0.026:
		tmp = -2.0 * math.pow(math.sin((eps * 0.5)), 2.0)
	elif eps <= 0.001:
		tmp = (-0.5 * (eps * (eps * math.cos(x)))) - (eps * math.sin(x))
	else:
		tmp = math.cos(eps) - math.cos(x)
	return tmp
function code(x, eps)
	tmp = 0.0
	if (eps <= -0.026)
		tmp = Float64(-2.0 * (sin(Float64(eps * 0.5)) ^ 2.0));
	elseif (eps <= 0.001)
		tmp = Float64(Float64(-0.5 * Float64(eps * Float64(eps * cos(x)))) - Float64(eps * sin(x)));
	else
		tmp = Float64(cos(eps) - cos(x));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if (eps <= -0.026)
		tmp = -2.0 * (sin((eps * 0.5)) ^ 2.0);
	elseif (eps <= 0.001)
		tmp = (-0.5 * (eps * (eps * cos(x)))) - (eps * sin(x));
	else
		tmp = cos(eps) - cos(x);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[eps, -0.026], N[(-2.0 * N[Power[N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 0.001], N[(N[(-0.5 * N[(eps * N[(eps * N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Cos[eps], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.026:\\
\;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\

\mathbf{elif}\;\varepsilon \leq 0.001:\\
\;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \varepsilon \cdot \sin x\\

\mathbf{else}:\\
\;\;\;\;\cos \varepsilon - \cos x\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -0.0259999999999999988

    1. Initial program 46.0%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos47.3%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv47.3%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. metadata-eval47.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. div-inv47.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      5. +-commutative47.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      6. metadata-eval47.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr47.3%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. *-commutative47.3%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \left(\left(x + \varepsilon\right) - x\right)\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      2. +-commutative47.3%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      3. associate--l+49.3%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      4. *-commutative49.3%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
      5. associate-+r+49.2%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right)\right) \]
      6. +-commutative49.2%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x + x\right)\right)}\right)\right) \]
    5. Simplified49.2%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)\right)} \]
    6. Taylor expanded in x around 0 49.1%

      \[\leadsto -2 \cdot \color{blue}{{\sin \left(0.5 \cdot \varepsilon\right)}^{2}} \]

    if -0.0259999999999999988 < eps < 1e-3

    1. Initial program 26.8%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 98.7%

      \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. mul-1-neg98.7%

        \[\leadsto -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)} \]
      2. unsub-neg98.7%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) - \varepsilon \cdot \sin x} \]
      3. unpow298.7%

        \[\leadsto -0.5 \cdot \left(\color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \cdot \cos x\right) - \varepsilon \cdot \sin x \]
      4. associate-*l*98.7%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right)} - \varepsilon \cdot \sin x \]
    4. Simplified98.7%

      \[\leadsto \color{blue}{-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \varepsilon \cdot \sin x} \]

    if 1e-3 < eps

    1. Initial program 52.2%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 54.7%

      \[\leadsto \color{blue}{\cos \varepsilon} - \cos x \]
  3. Recombined 3 regimes into one program.
  4. Final simplification73.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.026:\\ \;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\ \mathbf{elif}\;\varepsilon \leq 0.001:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\cos \varepsilon - \cos x\\ \end{array} \]

Alternative 9: 75.7% accurate, 1.0× speedup?

\[\begin{array}{l} \\ -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right) \end{array} \]
(FPCore (x eps)
 :precision binary64
 (* -2.0 (* (sin (/ eps 2.0)) (sin (* 0.5 (+ x (+ eps x)))))))
double code(double x, double eps) {
	return -2.0 * (sin((eps / 2.0)) * sin((0.5 * (x + (eps + x)))));
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = (-2.0d0) * (sin((eps / 2.0d0)) * sin((0.5d0 * (x + (eps + x)))))
end function
public static double code(double x, double eps) {
	return -2.0 * (Math.sin((eps / 2.0)) * Math.sin((0.5 * (x + (eps + x)))));
}
def code(x, eps):
	return -2.0 * (math.sin((eps / 2.0)) * math.sin((0.5 * (x + (eps + x)))))
function code(x, eps)
	return Float64(-2.0 * Float64(sin(Float64(eps / 2.0)) * sin(Float64(0.5 * Float64(x + Float64(eps + x))))))
end
function tmp = code(x, eps)
	tmp = -2.0 * (sin((eps / 2.0)) * sin((0.5 * (x + (eps + x)))));
end
code[x_, eps_] := N[(-2.0 * N[(N[Sin[N[(eps / 2.0), $MachinePrecision]], $MachinePrecision] * N[Sin[N[(0.5 * N[(x + N[(eps + x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
-2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right)
\end{array}
Derivation
  1. Initial program 38.6%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. add-log-exp38.6%

      \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
  3. Applied egg-rr38.6%

    \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
  4. Step-by-step derivation
    1. add-log-exp38.6%

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) - \cos x} \]
    2. diff-cos47.3%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    3. +-commutative47.3%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    4. associate-+r-72.9%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    5. +-inverses72.9%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + \color{blue}{0}}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    6. +-commutative72.9%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right)\right) \]
    7. associate-+r+73.0%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right)\right) \]
  5. Applied egg-rr73.0%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right)} \]
  6. Step-by-step derivation
    1. +-rgt-identity73.0%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon}}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right) \]
  7. Simplified73.0%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right)} \]
  8. Step-by-step derivation
    1. div-inv73.0%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \color{blue}{\left(\left(\varepsilon + \left(x + x\right)\right) \cdot \frac{1}{2}\right)}\right) \]
    2. metadata-eval73.0%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. *-commutative73.0%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)}\right) \]
    4. add-log-exp58.2%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \color{blue}{\log \left(e^{\sin \left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)}\right)}\right) \]
    5. *-commutative58.2%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \log \left(e^{\sin \color{blue}{\left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)}}\right)\right) \]
  9. Applied egg-rr58.2%

    \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \color{blue}{\log \left(e^{\sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)}\right)}\right) \]
  10. Step-by-step derivation
    1. add-log-exp73.0%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \color{blue}{\sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)}\right) \]
    2. associate-+r+72.9%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(\color{blue}{\left(\left(\varepsilon + x\right) + x\right)} \cdot 0.5\right)\right) \]
    3. +-commutative72.9%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(\color{blue}{\left(x + \left(\varepsilon + x\right)\right)} \cdot 0.5\right)\right) \]
    4. *-commutative72.9%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)}\right) \]
    5. +-commutative72.9%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(0.5 \cdot \left(x + \color{blue}{\left(x + \varepsilon\right)}\right)\right)\right) \]
  11. Applied egg-rr72.9%

    \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \color{blue}{\sin \left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
  12. Final simplification72.9%

    \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right) \]

Alternative 10: 75.7% accurate, 1.0× speedup?

\[\begin{array}{l} \\ -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right) \end{array} \]
(FPCore (x eps)
 :precision binary64
 (* -2.0 (* (sin (/ eps 2.0)) (sin (/ (+ eps (+ x x)) 2.0)))))
double code(double x, double eps) {
	return -2.0 * (sin((eps / 2.0)) * sin(((eps + (x + x)) / 2.0)));
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = (-2.0d0) * (sin((eps / 2.0d0)) * sin(((eps + (x + x)) / 2.0d0)))
end function
public static double code(double x, double eps) {
	return -2.0 * (Math.sin((eps / 2.0)) * Math.sin(((eps + (x + x)) / 2.0)));
}
def code(x, eps):
	return -2.0 * (math.sin((eps / 2.0)) * math.sin(((eps + (x + x)) / 2.0)))
function code(x, eps)
	return Float64(-2.0 * Float64(sin(Float64(eps / 2.0)) * sin(Float64(Float64(eps + Float64(x + x)) / 2.0))))
end
function tmp = code(x, eps)
	tmp = -2.0 * (sin((eps / 2.0)) * sin(((eps + (x + x)) / 2.0)));
end
code[x_, eps_] := N[(-2.0 * N[(N[Sin[N[(eps / 2.0), $MachinePrecision]], $MachinePrecision] * N[Sin[N[(N[(eps + N[(x + x), $MachinePrecision]), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
-2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right)
\end{array}
Derivation
  1. Initial program 38.6%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. add-log-exp38.6%

      \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
  3. Applied egg-rr38.6%

    \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
  4. Step-by-step derivation
    1. add-log-exp38.6%

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) - \cos x} \]
    2. diff-cos47.3%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    3. +-commutative47.3%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    4. associate-+r-72.9%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    5. +-inverses72.9%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + \color{blue}{0}}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    6. +-commutative72.9%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right)\right) \]
    7. associate-+r+73.0%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right)\right) \]
  5. Applied egg-rr73.0%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\varepsilon + 0}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right)} \]
  6. Step-by-step derivation
    1. +-rgt-identity73.0%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon}}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right) \]
  7. Simplified73.0%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right)} \]
  8. Final simplification73.0%

    \[\leadsto -2 \cdot \left(\sin \left(\frac{\varepsilon}{2}\right) \cdot \sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right)\right) \]

Alternative 11: 67.3% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -2.15 \cdot 10^{-20} \lor \neg \left(\varepsilon \leq 2 \cdot 10^{-23}\right):\\ \;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\ \mathbf{else}:\\ \;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -2.15e-20) (not (<= eps 2e-23)))
   (* -2.0 (pow (sin (* eps 0.5)) 2.0))
   (* (sin x) (- eps))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -2.15e-20) || !(eps <= 2e-23)) {
		tmp = -2.0 * pow(sin((eps * 0.5)), 2.0);
	} else {
		tmp = sin(x) * -eps;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-2.15d-20)) .or. (.not. (eps <= 2d-23))) then
        tmp = (-2.0d0) * (sin((eps * 0.5d0)) ** 2.0d0)
    else
        tmp = sin(x) * -eps
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -2.15e-20) || !(eps <= 2e-23)) {
		tmp = -2.0 * Math.pow(Math.sin((eps * 0.5)), 2.0);
	} else {
		tmp = Math.sin(x) * -eps;
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -2.15e-20) or not (eps <= 2e-23):
		tmp = -2.0 * math.pow(math.sin((eps * 0.5)), 2.0)
	else:
		tmp = math.sin(x) * -eps
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -2.15e-20) || !(eps <= 2e-23))
		tmp = Float64(-2.0 * (sin(Float64(eps * 0.5)) ^ 2.0));
	else
		tmp = Float64(sin(x) * Float64(-eps));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -2.15e-20) || ~((eps <= 2e-23)))
		tmp = -2.0 * (sin((eps * 0.5)) ^ 2.0);
	else
		tmp = sin(x) * -eps;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -2.15e-20], N[Not[LessEqual[eps, 2e-23]], $MachinePrecision]], N[(-2.0 * N[Power[N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision], N[(N[Sin[x], $MachinePrecision] * (-eps)), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -2.15 \cdot 10^{-20} \lor \neg \left(\varepsilon \leq 2 \cdot 10^{-23}\right):\\
\;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\

\mathbf{else}:\\
\;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -2.15000000000000006e-20 or 1.99999999999999992e-23 < eps

    1. Initial program 46.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos49.5%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv49.5%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. metadata-eval49.5%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. div-inv49.5%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      5. +-commutative49.5%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      6. metadata-eval49.5%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr49.5%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. *-commutative49.5%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \left(\left(x + \varepsilon\right) - x\right)\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      2. +-commutative49.5%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      3. associate--l+52.4%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      4. *-commutative52.4%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
      5. associate-+r+52.4%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right)\right) \]
      6. +-commutative52.4%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x + x\right)\right)}\right)\right) \]
    5. Simplified52.4%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \left(x - x\right)\right)\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)\right)} \]
    6. Taylor expanded in x around 0 51.1%

      \[\leadsto -2 \cdot \color{blue}{{\sin \left(0.5 \cdot \varepsilon\right)}^{2}} \]

    if -2.15000000000000006e-20 < eps < 1.99999999999999992e-23

    1. Initial program 28.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 84.6%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. associate-*r*84.6%

        \[\leadsto \color{blue}{\left(-1 \cdot \varepsilon\right) \cdot \sin x} \]
      2. mul-1-neg84.6%

        \[\leadsto \color{blue}{\left(-\varepsilon\right)} \cdot \sin x \]
    4. Simplified84.6%

      \[\leadsto \color{blue}{\left(-\varepsilon\right) \cdot \sin x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification65.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -2.15 \cdot 10^{-20} \lor \neg \left(\varepsilon \leq 2 \cdot 10^{-23}\right):\\ \;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\ \mathbf{else}:\\ \;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\ \end{array} \]

Alternative 12: 67.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.026:\\ \;\;\;\;\cos \varepsilon + -1\\ \mathbf{elif}\;\varepsilon \leq 0.00019:\\ \;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \varepsilon - \cos x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -0.026)
   (+ (cos eps) -1.0)
   (if (<= eps 0.00019) (* (sin x) (- eps)) (- (cos eps) (cos x)))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -0.026) {
		tmp = cos(eps) + -1.0;
	} else if (eps <= 0.00019) {
		tmp = sin(x) * -eps;
	} else {
		tmp = cos(eps) - cos(x);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if (eps <= (-0.026d0)) then
        tmp = cos(eps) + (-1.0d0)
    else if (eps <= 0.00019d0) then
        tmp = sin(x) * -eps
    else
        tmp = cos(eps) - cos(x)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if (eps <= -0.026) {
		tmp = Math.cos(eps) + -1.0;
	} else if (eps <= 0.00019) {
		tmp = Math.sin(x) * -eps;
	} else {
		tmp = Math.cos(eps) - Math.cos(x);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if eps <= -0.026:
		tmp = math.cos(eps) + -1.0
	elif eps <= 0.00019:
		tmp = math.sin(x) * -eps
	else:
		tmp = math.cos(eps) - math.cos(x)
	return tmp
function code(x, eps)
	tmp = 0.0
	if (eps <= -0.026)
		tmp = Float64(cos(eps) + -1.0);
	elseif (eps <= 0.00019)
		tmp = Float64(sin(x) * Float64(-eps));
	else
		tmp = Float64(cos(eps) - cos(x));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if (eps <= -0.026)
		tmp = cos(eps) + -1.0;
	elseif (eps <= 0.00019)
		tmp = sin(x) * -eps;
	else
		tmp = cos(eps) - cos(x);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[eps, -0.026], N[(N[Cos[eps], $MachinePrecision] + -1.0), $MachinePrecision], If[LessEqual[eps, 0.00019], N[(N[Sin[x], $MachinePrecision] * (-eps)), $MachinePrecision], N[(N[Cos[eps], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.026:\\
\;\;\;\;\cos \varepsilon + -1\\

\mathbf{elif}\;\varepsilon \leq 0.00019:\\
\;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\

\mathbf{else}:\\
\;\;\;\;\cos \varepsilon - \cos x\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -0.0259999999999999988

    1. Initial program 46.0%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 49.1%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]

    if -0.0259999999999999988 < eps < 1.9000000000000001e-4

    1. Initial program 26.8%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 80.5%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. associate-*r*80.5%

        \[\leadsto \color{blue}{\left(-1 \cdot \varepsilon\right) \cdot \sin x} \]
      2. mul-1-neg80.5%

        \[\leadsto \color{blue}{\left(-\varepsilon\right)} \cdot \sin x \]
    4. Simplified80.5%

      \[\leadsto \color{blue}{\left(-\varepsilon\right) \cdot \sin x} \]

    if 1.9000000000000001e-4 < eps

    1. Initial program 52.2%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 54.7%

      \[\leadsto \color{blue}{\cos \varepsilon} - \cos x \]
  3. Recombined 3 regimes into one program.
  4. Final simplification65.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.026:\\ \;\;\;\;\cos \varepsilon + -1\\ \mathbf{elif}\;\varepsilon \leq 0.00019:\\ \;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \varepsilon - \cos x\\ \end{array} \]

Alternative 13: 67.0% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.026 \lor \neg \left(\varepsilon \leq 0.00033\right):\\ \;\;\;\;\cos \varepsilon + -1\\ \mathbf{else}:\\ \;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -0.026) (not (<= eps 0.00033)))
   (+ (cos eps) -1.0)
   (* (sin x) (- eps))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.026) || !(eps <= 0.00033)) {
		tmp = cos(eps) + -1.0;
	} else {
		tmp = sin(x) * -eps;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-0.026d0)) .or. (.not. (eps <= 0.00033d0))) then
        tmp = cos(eps) + (-1.0d0)
    else
        tmp = sin(x) * -eps
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.026) || !(eps <= 0.00033)) {
		tmp = Math.cos(eps) + -1.0;
	} else {
		tmp = Math.sin(x) * -eps;
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -0.026) or not (eps <= 0.00033):
		tmp = math.cos(eps) + -1.0
	else:
		tmp = math.sin(x) * -eps
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -0.026) || !(eps <= 0.00033))
		tmp = Float64(cos(eps) + -1.0);
	else
		tmp = Float64(sin(x) * Float64(-eps));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -0.026) || ~((eps <= 0.00033)))
		tmp = cos(eps) + -1.0;
	else
		tmp = sin(x) * -eps;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -0.026], N[Not[LessEqual[eps, 0.00033]], $MachinePrecision]], N[(N[Cos[eps], $MachinePrecision] + -1.0), $MachinePrecision], N[(N[Sin[x], $MachinePrecision] * (-eps)), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.026 \lor \neg \left(\varepsilon \leq 0.00033\right):\\
\;\;\;\;\cos \varepsilon + -1\\

\mathbf{else}:\\
\;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -0.0259999999999999988 or 3.3e-4 < eps

    1. Initial program 48.9%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 50.7%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]

    if -0.0259999999999999988 < eps < 3.3e-4

    1. Initial program 26.8%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 80.5%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. associate-*r*80.5%

        \[\leadsto \color{blue}{\left(-1 \cdot \varepsilon\right) \cdot \sin x} \]
      2. mul-1-neg80.5%

        \[\leadsto \color{blue}{\left(-\varepsilon\right)} \cdot \sin x \]
    4. Simplified80.5%

      \[\leadsto \color{blue}{\left(-\varepsilon\right) \cdot \sin x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification64.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.026 \lor \neg \left(\varepsilon \leq 0.00033\right):\\ \;\;\;\;\cos \varepsilon + -1\\ \mathbf{else}:\\ \;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\ \end{array} \]

Alternative 14: 45.9% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.000155 \lor \neg \left(\varepsilon \leq 0.00019\right):\\ \;\;\;\;\cos \varepsilon + -1\\ \mathbf{else}:\\ \;\;\;\;\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -0.000155) (not (<= eps 0.00019)))
   (+ (cos eps) -1.0)
   (* (* eps eps) -0.5)))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.000155) || !(eps <= 0.00019)) {
		tmp = cos(eps) + -1.0;
	} else {
		tmp = (eps * eps) * -0.5;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-0.000155d0)) .or. (.not. (eps <= 0.00019d0))) then
        tmp = cos(eps) + (-1.0d0)
    else
        tmp = (eps * eps) * (-0.5d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.000155) || !(eps <= 0.00019)) {
		tmp = Math.cos(eps) + -1.0;
	} else {
		tmp = (eps * eps) * -0.5;
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -0.000155) or not (eps <= 0.00019):
		tmp = math.cos(eps) + -1.0
	else:
		tmp = (eps * eps) * -0.5
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -0.000155) || !(eps <= 0.00019))
		tmp = Float64(cos(eps) + -1.0);
	else
		tmp = Float64(Float64(eps * eps) * -0.5);
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -0.000155) || ~((eps <= 0.00019)))
		tmp = cos(eps) + -1.0;
	else
		tmp = (eps * eps) * -0.5;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -0.000155], N[Not[LessEqual[eps, 0.00019]], $MachinePrecision]], N[(N[Cos[eps], $MachinePrecision] + -1.0), $MachinePrecision], N[(N[(eps * eps), $MachinePrecision] * -0.5), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.000155 \lor \neg \left(\varepsilon \leq 0.00019\right):\\
\;\;\;\;\cos \varepsilon + -1\\

\mathbf{else}:\\
\;\;\;\;\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -1.55e-4 or 1.9000000000000001e-4 < eps

    1. Initial program 48.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 50.3%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]

    if -1.55e-4 < eps < 1.9000000000000001e-4

    1. Initial program 27.0%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 27.0%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
    3. Taylor expanded in eps around 0 43.1%

      \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
    4. Step-by-step derivation
      1. *-commutative43.1%

        \[\leadsto \color{blue}{{\varepsilon}^{2} \cdot -0.5} \]
      2. unpow243.1%

        \[\leadsto \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \cdot -0.5 \]
    5. Simplified43.1%

      \[\leadsto \color{blue}{\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification47.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.000155 \lor \neg \left(\varepsilon \leq 0.00019\right):\\ \;\;\;\;\cos \varepsilon + -1\\ \mathbf{else}:\\ \;\;\;\;\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5\\ \end{array} \]

Alternative 15: 21.0% accurate, 41.0× speedup?

\[\begin{array}{l} \\ \left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 \end{array} \]
(FPCore (x eps) :precision binary64 (* (* eps eps) -0.5))
double code(double x, double eps) {
	return (eps * eps) * -0.5;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = (eps * eps) * (-0.5d0)
end function
public static double code(double x, double eps) {
	return (eps * eps) * -0.5;
}
def code(x, eps):
	return (eps * eps) * -0.5
function code(x, eps)
	return Float64(Float64(eps * eps) * -0.5)
end
function tmp = code(x, eps)
	tmp = (eps * eps) * -0.5;
end
code[x_, eps_] := N[(N[(eps * eps), $MachinePrecision] * -0.5), $MachinePrecision]
\begin{array}{l}

\\
\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5
\end{array}
Derivation
  1. Initial program 38.6%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Taylor expanded in x around 0 39.6%

    \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
  3. Taylor expanded in eps around 0 22.1%

    \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
  4. Step-by-step derivation
    1. *-commutative22.1%

      \[\leadsto \color{blue}{{\varepsilon}^{2} \cdot -0.5} \]
    2. unpow222.1%

      \[\leadsto \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \cdot -0.5 \]
  5. Simplified22.1%

    \[\leadsto \color{blue}{\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5} \]
  6. Final simplification22.1%

    \[\leadsto \left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 \]

Reproduce

?
herbie shell --seed 2023258 
(FPCore (x eps)
  :name "2cos (problem 3.3.5)"
  :precision binary64
  (- (cos (+ x eps)) (cos x)))